1. Prior Art
The broadcasting of the programs and services of digital television has been to a great extent defined by the DVB consortium. Its architecture has been built around on several standards linked to the broadcasting of information flows or streams. Thus, the DVB services (TV programs, radio programs, channel selectors) are transported in multiplexed form in traditional broadcasting networks such as satellite networks and wireless networks. These multiplexes are constituted by multiplex operators. Each multiplex is referenced when manufactured by the unique identifier of the multiplex operator known as the ORGINAL_NETWORK_ID (or ONiD) as well as a multiplex identifier known as TRANSPORT_STREAM_ID (or TSiD). This pair {ONiD; TSiD} represents the unique address of a multiplex. Within a multiplex, an identifier is allocated to each DVB service known as SERVICE_ID (or SiD). The triplet {ONiD, TSiD, SiD} represents the unique address of a DVB service, for example a television channel. This address is used by the terminal of the user (digital decoder) to identify, decode and present the television program or radio program selected beforehand by the user.
The multicast services in IP-based communications networks are, for their part, defined by the multicast addressing principle. This addressing is done on an addressing range reserved for multicasting. Multicast addressing enables the broadcasting on an IP architecture of a same piece of information to a group of customers. Each IP information packet (datagram) contains a source address and an address known as a single-destination multicast address. A user asks for a multicast content, identified by a multicast IP address, by means of the IGMP (Internet Group Management Protocol) on the networks that implement the version 4 of the IP (IPv4) or by means of the MLD (Multicast Listener Discovery) protocol on networks that implement IP version 6 (IPv6). Thus, when a user links up through an Internet connection to an information broadcasting service, the application responsible for identifying, decoding and presenting this service in question will retrieve the datagrams whose destination address is that of the information broadcasting service.
The DVB consortium has specified the mechanisms for transporting and signaling DVB-on-IP services. This DVB-IP specification has been standardized at the ESTI (European Telecommunications Standardization Institute). These signals are thus packaged in IP datagrams. DVB has also defined a mechanism of service discovery and selection. This mechanism called SD&S (Service Discovery and Selection) provides, a table for the translation of addresses between the DVB and IP worlds in the form of metadata. For each DVB service, these items of metadata provide the pair consisting of the DVB address and the associated multicast IP address. The multicast IP addresses are defined by the operators controlling the gateways between the DVB world and the IP world.
2. Drawbacks of the Prior Art
One drawback of this prior art technique is related to the passage from the DVB world to the IP world. Indeed, only the operators are able to define the pairs {DVB address; associated multicast IP address} to authenticate services. The allocation of the addressing pairs without concentration between the operators does not make it possible to ensure the uniqueness of the pairs {DVB address; associated multicast IP address}.
A corollary drawback of this technique is that nowadays broadcasting networks of the operators are completely closed. Indeed, since the operator defines his own addressing plan, this plan is known only to the operator in question. This partitioning therefore limits the possibility of supplying new services. To add a new service, an independent provider has two possibilities:                he must obtain a multicast address from an operator;        he must do without operators and use any multicast address at the risk of it's being an address already used by an operator.        
Yet another drawback of this prior art technique is that the uniqueness of a DVB service identified by its DVB address is no longer ensured during the encapsulation of the information stream in IP format. Indeed, a same IP address assigned to a DVB service can be re-used by another operator, another service or again by home gateways which can thus propose also the distribution of DVB-on-IP signals (locally on a user's private network for example) and cause problems of address overlapping. The deterioration of this uniqueness furthermore gives rise to a loss, at the transport level of the IP network, of the information on the original DVB multiplex, namely the triplet (formed by {ONiD; TSiD; SiD}).
Another drawback of this prior art technique is that the addition of a new broadcasting service in the IP world necessarily requires the creation of a pair {DVB address; associated multicast IP address} by the operator before this service can be broadcast on the IP network. This static approach cannot be envisaged for large-scale broadcasting.